The Easy way to make your Dolmar/solo unlimited

[ECsaws]

OK your going to need a coil from a 50, 51, 55, 61, 254, 257, 261, 262, 266, 268K, 272 few other will work also.
A dremel / something to grind the key out of the dolmar flywheel.
A degree wheel - be able to find TDC.

1st pull flywheel grind off key on the 7900/ remove key on 681.
Pull the original coil from your saw remove the core (your going to reuse it)
Remove the core from your 50, 51, 55, 61, 254, 257, 261, 262, 266, 268K, 272 etc...
Install your Husky coil on the dolmar core mount it in the case.
Now open my PDF file and finish the Job... easy peasy.
I have done many this way .. as long as you have TDC it puts the timing spot on.
Edit:: Magnet side of the flywheel must face the coil @ TDC

 

[Kemper]

That does look simple!

:msp_wink:

 

[gink595]

The coil swap will make it run like this one, correct? :msp_smile:

[video=youtube;KrOKQUy24Q8]http://www.youtube.com/watch?v=KrOKQUy24Q8[/video]

 

[procarbine2k1]

The coil swap will make it run like this one, correct? :msp_smile:

Wow that saw frikkin moves!

 

[gink595]

Wow that saw frikkin moves!

I don't know, does it sound like it holds RPM very well?:hmm3grin2orange:

 

[procarbine2k1]

I don't know, does it sound like it holds RPM very well?:hmm3grin2orange:

It seems as such haha

 

[rmh3481]

Sweet. Thank you for posting this up.

 

[MCW]

The coil swap will make it run like this one, correct? :msp_smile:

It's four stroking a bit too much in the cut Gink. Therefore it's slow

 

[ECsaws]

Yes its a fairly simple to unlimit one and it works great. all though a bit tricky to tune a modded 7900/681 IMO the limited coil makes more power. I have neaver found a reason to twist a works saw to the moon out of the wood as long as they clean up good in the wood.
Ya I know Franks 7900 is a bit on the fat side in that video just doing some testing. remember fuel makes power to a certain extent.
I would really like to put Jason's 681 up aginst franks 7900. IMO the solo will rule.
Here are a couple more saws I did , videos for a NY GTG. 12x12
Franks 880 work saw running a 10pin sprocket and Nate's 3120 running a 11 pin.[video=youtube;_vL_A5cpYH0]http://www.youtube.com/watch?v=_vL_A5cpYH0&feature=player_embedded[/video]

 

[gink595]

It's four stroking a bit too much in the cut Gink. Therefore it's slow

At least it is a easy fix! :hmm3grin2orange:

 

[MCW]

At least it is a easy fix! :hmm3grin2orange:

Push harder with a 42" bar buried?

 

[gink595]

I'm going to make a vid of it pulling a big bar. I have a ok sized oak trunk out back.

 

[MCW]

I'm going to make a vid of it pulling a big bar. I have a ok sized oak trunk out back.

I took a video of mine pulling a 42" bar buried in Redgum. Yours has got more stonk than that. Go a 60"

 

[nmurph]

Yes its a fairly simple to unlimit one and it works great. all though a bit tricky to tune a modded 7900/681 IMO the limited coil makes more power. I have neaver found a reason to twist a works saw to the moon out of the wood as long as they clean up good in the wood.
Ya I know Franks 7900 is a bit on the fat side in that video just doing some testing. remember fuel makes power to a certain extent.
I would really like to put Jason's 681 up aginst franks 7900. IMO the solo will rule.
Here are a couple more saws I did , videos for a NY GTG. 12x12
Franks 880 work saw running a 10pin sprocket and Nate's 3120 running a 11 pin.[video=youtube;_vL_A5cpYH0]http://www.youtube.com/watch?v=_vL_A5cpYH0&feature=player_embedded[/video]

Dragging a mature post up-

Eric, do you care to elaborate on how much you think you lose with the unlimited coil? Im guessing you would probably need a stop watch to see a difference? I would much prefer an unlimited coil on a ported saw rather than having to adjust a saw in a log. I can do it, but I would rather be able to fire it up and listen to it.

 

[blsnelling]

If toy get the timing advance set right, how would an unlimited coil be slower?

 

[MCW]

If toy get the timing advance set right, how would an unlimited coil be slower?

Maybe the unlimited coils lose spark power because it's like all free unguided sparks flying around and they get lost and stuff?

 

[David (saltas)]

why a unlimited coil might reduce the power

I may be that the unlimited coil is running at a frequency that is too fast for the magnetic flux to saturate the silicon steel laminations in the coil.
If this is true then when then magnetic field collapses the induced back emf will smaller and the amount of millijoules of energy in the spark will be reduced.
A lower millijoule spark cannot light the fuel mix as easily or as quickly and results in a retarded firing or a failure to ignite.

This is hypothetical, but based on real world electrical engineering theory, Testing can and would be able to prove it.

My gut feeling is not likely in this case

 

[MCW]

I may be that the unlimited coil is running at a frequency that is too fast for the magnetic flux to saturate the silicon steel laminations in the coil.
If this is true then when then magnetic field collapses the induced back emf will smaller and the amount of millijoules of energy in the spark will be reduced.
A lower millijoule spark cannot light the fuel mix as easily or as quickly and results in a retarded firing or a failure to ignite.

This is hypothetical, but based on real world electrical engineering theory, Testing can and would be able to prove it.

My gut feeling is not likely in this case

Somehow I read "Flux Capacitor" to start with and thought you were pulling a swifty Then I read it again and realised I'd misread it and you weren't cracking funnies Good info regardless of whether that's the case here or not

 

[DB43725]

Timming

Would it not hurt to advance the timmming somewhat,, because by the pic it show TDC.

 

[Eccentric]

Somehow I read "Flux Capacitor" to start with and thought you were pulling a swifty Then I read it again and realised I'd misread it and you weren't cracking funnies Good info regardless of whether that's the case here or not

Once you rev past 8800 RPM, the spark travels back in time due to the flux capacitor. Suddenly the engine wants to run like a 1955 saw.:jester: